Integrated motor and pump assembly

ABSTRACT

A pump assembly that includes a crankshaft having main journals and crankpin journals, rods operatively coupled with the crankpin journals, reciprocating members operatively coupled with the rods, and an electric motor operable to rotate the crankshaft. The electric motor includes a stator and a rotor. The rotor is directly connected with the crankshaft and is operable to rotate the crankshaft to move the plurality of rods and reciprocating members to move a fluid.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to and the benefit of U.S. ProvisionalApplication No. 61/973,065 entitled “Integrated Electric Motor Power-endfor Reciprocating Pumps,” filed Mar. 31, 2014, the entire disclosure ofwhich is hereby incorporated herein by reference.

Background of the Disclosure

In oilfield operations, reciprocating pumps are utilized at wellsitesfor large scale, high-pressure operations. Such operations may includedrilling, cementing, acidizing, water jet cutting, and hydraulicfracturing of subterranean formations. In some applications, severalpumps may be connected in parallel to a single manifold, flow line, orwell. Some reciprocating pumps include reciprocating members driven by acrankshaft toward and away from a fluid chamber to alternatingly drawin, pressurize, and expel fluid from the fluid chamber. Hydraulicfracturing of a subterranean formation, for example, may utilize fluidat a pressure exceeding 10,000 PSI.

The success of pumping operations can be affected by many factors of thepumps, including physical size, weight, energy efficiency, and abilityto collectively control individual pumps operating at the wellsite.Reciprocating pumps may have a large physical size and weight to satisfyintended fluid flow rates during oilfield operations. Accordingly, oneor more pumps may be mounted on a truck or a skid for transportation tothe wellsite. However, due to their size and/or weight, a limited numberof pumps may be mounted on a single truck or skid. The pumps may alsoinclude a diesel engine or an asynchronous AC electric motor as part ofa power section of the pump driving a fluid section of the pump.However, diesel engines and some asynchronous AC electric motors operateat high speeds, such as 1500 to 2000 revolutions per minute (RPM), andthe fluid section of the pump operates at low speeds, such as 300 to 400RPM, a gear box, chain case, or other transmission is included in thepower section to operatively couple the engine/motor with thecrankshaft. This also increases the size, weight, and cost of thepump(s). Moreover, each engine is individually fueled and controlled,which limits flexibility and control over a collective pumping systemwhen multiple pumps are being operated simultaneously.

SUMMARY OF THE DISCLOSURE

This summary is provided to introduce a selection of concepts that arefurther described below in the detailed description. This summary is notintended to identify indispensable features of the claimed subjectmatter, nor is it intended for use as an aid in limiting the scope ofthe claimed subject matter.

The present disclosure introduces an apparatus that includes a pumpassembly. The pump assembly includes a drive shaft, rods operativelycoupled with the drive shaft, reciprocating members each operativelycoupled with a corresponding one of the rods, and an electric motoroperable to rotate the drive shaft. The electric motor includes a rotorhaving a rotor shaft. The rotor shaft is connected with the drive shaftand is operable to rotate the drive shaft and thus move the rods andreciprocating members. The rotor shaft and the drive shaft rotate at thesame speed. The reciprocating members are operable to move a fluid.

The present disclosure also introduces an apparatus that includes a pumpassembly having a crankshaft. The crankshaft includes main journals andcrankpin journals. The pump assembly also includes rods each operativelycoupled with a corresponding one of the crankpin journals, reciprocatingmembers each operatively coupled with a corresponding one of the rods,and an electric motor operable to rotate the crankshaft. The electricmotor includes a stator and a rotor. The rotor is directly connectedwith the crankshaft and is operable to rotate the crankshaft and thusmove the rods, thereby causing the plurality of reciprocating members tomove a fluid.

The present disclosure also introduces a method that includes connectinga fluid source to a pump assembly. The pump assembly includes a driveshaft, rods operatively coupled with the drive shaft, reciprocatingmembers operatively coupled with the rods, and an electric motor thatincludes a stator and a rotor that is directly connected with the driveshaft. The method also includes operating the electric motor to rotatethe rotor and the drive shaft at the same speed such that the rotatingdrive shaft moves the rods and reciprocating members to pump the fluidfrom the fluid source through the pump assembly.

These and additional aspects of the present disclosure are set forth inthe description that follows, and/or may be learned by a person havingordinary skill in the art by reading the materials herein and/orpracticing the principles described herein. At least some aspects of thepresent disclosure may be achieved via means recited in the attachedclaims.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure is understood from the following detaileddescription when read with the accompanying figures. It is emphasizedthat, in accordance with the standard practice in the industry, variousfeatures are not drawn to scale. In fact, the dimensions of the variousfeatures may be arbitrarily increased or reduced for clarity ofdiscussion.

FIG. 1 is a schematic view of at least a portion of apparatus accordingto one or more aspects of the present disclosure.

FIG. 2 is a perspective view of a portion of an example implementationof the apparatus shown in FIG. 1 according to one or more aspects of thepresent disclosure.

FIG. 3 is a side sectional view of a portion of an exampleimplementation of the apparatus shown in FIG. 1 according to one or moreaspects of the present disclosure.

FIG. 4 is a top partial sectional view of a portion of an exampleimplementation of the apparatus shown in FIG. 3 according to one or moreaspects of the present disclosure.

FIG. 5 is a side sectional view of a portion of an exampleimplementation of the apparatus shown in FIG. 1 according to one or moreaspects of the present disclosure.

FIG. 6 is a top partial sectional view of a portion of an exampleimplementation of the apparatus shown in FIG. 5 according to one or moreaspects of the present disclosure.

FIG. 7 is a top partial sectional view of a portion of an exampleimplementation of the apparatus shown in FIG. 1 according to one or moreaspects of the present disclosure.

FIG. 8 is a top partial sectional view of a portion of an exampleimplementation of the apparatus shown in FIG. 1 according to one or moreaspects of the present disclosure.

FIG. 9 is a schematic view of a portion of an example implementation ofthe apparatus shown in FIG. 1 according to one or more aspects of thepresent disclosure.

FIG. 10 is a flow-chart diagram of at least a portion of a methodaccording to one or more aspects of the present disclosure.

DETAILED DESCRIPTION

It is to be understood that the following disclosure provides manydifferent embodiments, or examples, for implementing different featuresof various embodiments. Specific examples of components and arrangementsare described below to simplify the present disclosure. These are, ofcourse, merely examples and are not intended to be limiting. Inaddition, the present disclosure may repeat reference numerals and/orletters in the various examples. This repetition is for simplicity andclarity, and does not in itself dictate a relationship between thevarious embodiments and/or configurations discussed. Moreover, theformation of a first feature over or on a second feature in thedescription that follows may include embodiments in which the first andsecond features are formed in direct contact, and may also includeembodiments in which additional features may be formed interposing thefirst and second features, such that the first and second features maynot be in direct contact.

FIG. 1 is a schematic view of at least a portion of an example pumpingsystem 100 according to one or more aspects of the present disclosure.The figure depicts a wellsite surface 102 adjacent to a wellbore 104 anda partial sectional view of a subterranean formation 106 penetrated bythe wellbore 104 below the wellsite surface 102. The pumping system 100may comprise a first mixer 108 fluidly connected with one or more tanks110 and a first container 112. The first container 112 may contain afirst material and the tanks 110 may contain a liquid. The firstmaterial may be or comprise a hydratable material or gelling agent, suchas guar, a polymer, a synthetic polymer, a galactomannan, apolysaccharide, a cellulose, and/or a clay, among other examples, andthe liquid may be or comprise an aqueous fluid, which may comprise wateror an aqueous solution comprising water, among other examples. The firstmixer 108 may be operable to receive the first material and the liquid,as indicated by arrows 114, 116, and mix or otherwise combine the firstmaterial and the liquid to form a base fluid. The base fluid may be orcomprise that which is known in the art as a gel. The first mixer 108may then discharge the base fluid, as indicated by arrow 118.

The first mixer 108 and the first container 112 may each be disposed oncorresponding trucks, trailers, and/or other mobile carriers 120, 122,respectively, such as may permit their transportation to the wellsitesurface 102. However, the first mixer 108 and/or the first container 112may be skidded or otherwise stationary, and/or may be temporarily orpermanently installed at the wellsite surface 102.

The pumping system 100 may further comprise a second mixer 124 fluidlyconnected with the first mixer 108 and a second container 126. Thesecond container 126 may contain a second material that may besubstantially different than the first material. For example, the secondmaterial may be or comprise a proppant material, such as may comprisesand, sand-like particles, silica, quartz, and/or propping agents, amongother examples.

The second mixer 124 may be operable to receive the base fluid from thefirst mixer 108, as indicated by arrow 118, and the second material fromthe second container 126, as indicated by arrow 128, and mix orotherwise combine the base fluid and the second material to form amixture. The mixture may be or comprise that which is known in the artas a fracturing fluid. The second mixer 124 may then discharge themixture, as indicated by arrow 130.

The second mixer 124 and the second container 126 may each be disposedon corresponding trucks, trailers, and/or other mobile carriers 132,134, respectively, such as may permit their transportation to thewellsite surface 102. However, the second mixer 124 and/or the secondcontainer 126 may be skidded or otherwise stationary, and/or may betemporarily or permanently installed at the wellsite surface 102.

The mixture may be communicated from the second mixer 124 to a commonmanifold 136, as indicated by arrow 130. The manifold 136 may comprise aplurality of valves, diverters, and/or other fluid pathways 150 operableto direct the mixture in a predetermined and/or selective manner. Themanifold 136, which may be known in the art as a missile or a missiletrailer, may distribute the mixture to one or more pump assemblies 200.Each pump assembly 200 may receive the mixture from the manifold 136 oranother conduit, as indicated by arrows 138, and discharge the mixtureto the manifold 136 or another conduit, as indicated by arrows 140. Themixture may then be discharged from the manifold 136 into the wellbore104, as indicated by arrow 142, perhaps through various valves,conduits, and/or other hydraulic circuitry fluidly connected between themanifold 136 and the wellbore 104.

The pump assemblies 200 may each be mounted on corresponding trucks,trailers, and/or other mobile carriers 144, such as may permit theirtransportation to the wellsite surface 102. However, the pump assemblies200 may be skidded or otherwise stationary, and/or may be temporarily orpermanently installed at the wellsite surface 102. Although each mobilecarrier 144 is shown carrying three pump assemblies 200, otherquantities of pump assemblies 200 are within the scope of the presentdisclosure. For example, each mobile carrier 144 may carry one, two,four, or more pump assemblies 200.

The pumping system 100 may also comprise a control center 146 and asource of electric power 148, such as may be collectively utilized as acentralized power distribution system operable to control and/or provideelectric power to one or more portions of the pumping system 100. Thesource of electric power 148 may be or comprise an engine-generator set,such as a gas turbine generator, an internal combustion enginegenerator, or other sources of electrical power known in the art.Electric power and/or control signals may be communicated between thecontrol center 146, the source of electric power 148, and other wellsiteequipment via electrical conductors 152 extending therebetween. However,other means of communication, such as wireless communication, is alsowithin the scope of the present disclosure.

The control center 146 may be utilized to control at least a portion ofthe pumping system 100 during pumping operations, including the mixers108, 124 and the pump assemblies 200. For example, the control center146 may be operable to control the production rate of the mixture, suchas by increasing or decreasing the flow of the liquid from the tanks110, the first material from the first container 112, the base fluidfrom the first mixer 108, the second material from the second container126, and/or the mixture from the second mixer 124. The control center146 may also be operable to control the speed of individual electricalmotors 250, shown in FIGS. 3-9, such as may be operable to control thespeed of the pump assemblies 200 and, therefore, the output flow rate ofeach pump assembly 200. The control center 146 may comprise one or morevariable speed drives (VSD) (not shown), which may facilitate speedcontrol of the electric motors 250. In other implementations of thepumping system 100, the one or more VSDs may be disposed adjacent to orin association with each pump assembly 200 or a fleet of pump assemblies200. The control center 146 may also be operable to control the outputpressure of the mixture or other fluid discharged from each of the pumpassemblies 200.

Furthermore, the control center 146 may be operable to pair the valvesof the manifold 136 with the pump assemblies 200 to create an interlockbetween the pump assemblies 200 and the manifold 136. The control center146 may also be operable to fluidly connect and disconnect predeterminedpump assemblies 200 from the internal fluid pathways 150 through themanifold 136. The control center 146 may also be operable to controlpower distribution between the source of electric power 148 and thefirst mixer 108, the second mixer 124, the pump assemblies 200, andother pumps and/or conveyers (not shown).

The control center 146 and the source of electric power 148 may bedisposed on a corresponding truck, trailer, and/or other mobile carrier154, 156, such as may permit its transportation to the wellsite surface102. However, the control center 146 and the source of electric power148 may be skidded or otherwise stationary, and/or may be temporarily orpermanently installed at the wellsite surface 102.

FIG. 2 is a perspective view of an example implementation of the pumpassembly 200 shown in FIG. 1 according to one or more aspects of thepresent disclosure. FIG. 3 is a side sectional view of a portion of thepump assembly 200 shown in FIG. 2. The following description refers toFIGS. 2 and 3, collectively.

The pump assembly 200 may be or comprise a reciprocating pump assemblyhaving a power section 202 and a fluid section 210. The fluid section210 may comprise a pump housing 216 having a plurality of fluid chambers218 extending therethrough in a substantially parallel configuration.One end of each fluid chamber 218 may be plugged by a cover plate 220,which may be threadedly engaged with the pump housing 216. The oppositeend of each chamber 218 may contain a reciprocating member 222 slidablydisposed therein. Although the reciprocating member 222 is depicted as aplunger, the reciprocating member 222 may be implemented as a piston,diaphragm, or another reciprocating member.

Each fluid chamber 218 may be fluidly connected with a correspondingfluid inlet cavity 224 adapted for communicating the fluid into eachfluid chamber 218 from a fluid inlet conduit 226. Each fluid inletcavity 224 may contain an inlet valve 228, which may be operable tocontrol the flow of fluid from the fluid inlet conduit 226 to the fluidchamber 218. Each inlet valve 228 may be biased toward a closed positionby a first spring 230, which may be held in place by an inlet valve stop232. Each inlet valve 228 may be actuated to an open position by aselected or predetermined differential pressure between the fluid inletcavity 224 and the fluid inlet conduit 226. The fluid inlet conduit 226may be fluidly connected with a low pressure fluid outlet (not shown) ofthe manifold 136 or another fluid conduit for supplying the mixture oranother fluid to be pumped by the pump assembly 200.

Each fluid chamber 218 may also be fluidly connected with a fluid outletcavity 234 extending through the pump housing 216, such as may beadapted for communicating pressurized fluid from each fluid chamber 218into one or more fluid outlet conduits 235. The fluid outlet cavity 234may contain therein a plurality of outlet valves 236, which may beoperable to control fluid flow out of the fluid chambers 218 into thefluid outlet cavity 234. The outlet valves 236 may be biased toward aclosed position by a second spring 238, which may be held in place by anoutlet valve stop 240. The outlet valve 236 may be actuated to an openposition by a predetermined differential pressure between the fluidchamber 218 and the fluid outlet cavity 234. The fluid outlet cavity 234may be plugged by a plurality of second cover plates 242, which may bethreadedly engaged with the pump housing 216, while one or both ends ofthe fluid outlet cavity 234 may be fluidly coupled with the one or morefluid outlet conduits 235. The fluid outlet conduits 235 may be fluidlyconnected to a high-pressure inlet (not shown) of the manifold 136 oranother destination for the pressurized mixture or fluid.

During pumping operations, portions of the power section 202 of the pumpassembly 200 may rotate to generate a reciprocating linear force, suchas may move the reciprocating members 222 longitudinally within thecorresponding fluid chambers 218. With regard to each reciprocatingmember 222, as the reciprocating member 222 moves out of the fluidchamber 218, as indicated by arrow 221, the pressure of the fluid insidethe fluid chamber 218 decreases, thus creating a differential pressureacross the fluid inlet valve 228, which actuates the fluid inlet valve228 to permit the mixture or other fluid from the fluid inlet conduit226 to enter the fluid inlet cavity 224 and the fluid chamber 218. Thefluid then enters the fluid chamber 218 as the reciprocating member 222continues to move longitudinally out of the fluid chamber 218 until thepressure difference between the fluid inside the fluid chamber 218 andthe fluid within the fluid inlet conduit 226 is low enough, thuspermitting the first spring 230 to actuate the fluid inlet valve 228 tothe closed position. As the reciprocating member 222 begins to movelongitudinally back into the fluid chamber 218, as indicated by arrow223, the pressure of the fluid inside of fluid chamber 218 begins toincrease. The fluid pressure inside the fluid chamber 218 continues toincrease as the reciprocating member 222 continues to move into thefluid chamber 218 until the pressure difference between the fluid insidethe fluid chamber 218 and the fluid inside the fluid outlet cavity 234is high enough to compress the second spring 238, thus actuating thefluid outlet valve 236 to the open position and permitting thepressurized fluid to move into the fluid outlet cavity 234 and the fluidoutlet conduit 235. Thereafter, the fluid may be communicated to themanifold 136, as depicted in FIG. 1, or to another destination forpressurized mixture or fluid.

The fluid flow rate generated by the pump assembly 200 may depend on thephysical size of the reciprocating members 222 and fluid chambers 218,as well as the speed or rate at which the reciprocating members 222 movewithin the fluid chambers 218. The speed or rate at which thereciprocating members 222 move is directly related to the rotationalspeed of the power section 202, such that the fluid flow rate may becontrolled by the rotational speed of the power section 202.

The power section 202 of the pump assembly 200 may also comprise a powersection housing 254 enclosing an electric motor 250, which may bedisposed about a drive shaft 252. The electric motor 250 is operable todrive or otherwise rotate the drive shaft 252. The electric motor 250may comprise a motor housing 255 enclosing a stator 256 and a rotor 258.The stator 256 may be or comprise a plurality of field coils orwindings, such as may generate a magnetic field when powered by electriccurrent from the source of electric power 148 or another source ofelectric power. The stator 256 may define an axial opening containingthe rotor 258 and through which the drive shaft 252 extends. The rotor258 may comprise a plurality of windings or permanent magnets 259fixedly disposed about a rotor shaft 260. The rotor shaft 260 may be ahollow shaft or comprise an axial bore 261 through which the drive shaft252 extends. The rotor shaft 260 or another portion of the rotor 258 maybe directly and/or otherwise fixedly coupled with the drive shaft 252,such that the rotor shaft 260 may transmit torque from the rotor 258directly to the drive shaft 252. Thus, because the rotor shaft 260 andthe drive shaft 252 are directly and/or otherwise fixedly coupled, therotor shaft 260 and the drive shaft 252 may rotate at the same speed orrate. The electric motors 250 utilized within the scope of the presentdisclosure may include, for example, synchronous and asynchronouselectric motors, such as may be operable to rotate at selected speedsbetween zero and about 500 RPM, although other speeds are also withinthe scope of the present disclosure. For example, the electric motors250 may rotate at speeds between about 300 RPM and about 400 RPM.

The directly and/or otherwise fixedly coupled relationship between therotor shaft 260 and the drive shaft 252 may be interpreted to include animplementation of the pump assembly 200 in which the rotor shaft 260 andthe drive shaft 252 are in direct contact with each other, thuspreventing relative rotation between the rotor shaft 260 and the driveshaft 252 such that the rotor shaft 260 and the drive shaft 252 rotateat the same speed or rate. The directly and/or otherwise fixedly coupledrelationship between the rotor shaft 260 and the drive shaft 252 mayalso be interpreted to include an implementation of the pump assembly200 in which the rotor shaft 260 and the drive shaft 252 are not indirect contact, but are connected by one or more rigid interveningmembers collectively fixedly connecting the rotor shaft 260 and thedrive shaft 252 together, such as a ring (not shown), in a mannerpreventing relative rotation between the rotor shaft 260 and the driveshaft 252 such that the rotor shaft 260 and the drive shaft 252 rotateat the same speed or rate. However, the directly and/or otherwisefixedly coupled relationship between the rotor shaft 260 and the driveshaft 252 is not intended to be interpreted to include implementationsin which rotation of the drive shaft 252 is facilitated by atransmission, gearbox, gear train, or other similar mechanismoperatively connecting the rotor shaft 260 and the drive shaft 252.

FIG. 4 is a top partial sectional view of a portion of an exampleimplementation of the pump assembly 200 shown in FIG. 3 according to oneor more aspects of the present disclosure. Referring to FIGS. 3 and 4,collectively, the drive shaft 252 may be implemented as a crankshaftcomprising a plurality of support journals 262, main journals 264, andcrankpin journals 266. The support and main journals 262, 264 may extendalong a central axis of rotation 268 of the drive shaft 252, while thecrankpin journals 266 may be offset from the central axis of rotation268 by a predetermined distance and spaced 120 degrees apart withrespect to the support journals 262 and main journals 264.

FIG. 4 shows an example implementation of the pump assembly 200comprising two electric motors 250 disposed about the drive shaft 252.As shown, the rotor shaft 260 of each motor 250 may be disposed aboutand directly and/or otherwise fixedly connected with two of the mainjournals 264, such as may facilitate transfer of torque from the motors250 directly to the drive shaft 252 to rotate the drive shaft 252 whenthe motors are powered. To prevent relative rotation between the powersection housing 254 and the motors 250, the power section housing 254and motor housing 255 may be fixedly coupled together. Although theexample implementation of the pump assembly 200 shown in FIG. 4comprises two electric motors 250, it is to be understood that otherquantities of electric motors 250 may be incorporated as part of thepump assembly 200. For example, a drive shaft 252 comprising six mainjournals 264 may comprise one, two, three, four, or more electric motors250, which are connected with and/or distributed between the six mainjournals 264.

When two or more separate electric motors 250 are utilized to rotate thedrive shaft 252, the electrical motors 250 may need to be synchronizedto run at the same speed by synchronizing the VSDs, such as during rampup, ramp down, and steady speed motor conditions. Torque limits may alsobe set on the VSDs to limit and/or prevent twisting or deformation ofthe drive shaft 252, such as when the electric motors 250 are notsynchronized.

The drive shaft 252 and the rotor shaft 260 may be directly and/orotherwise fixedly coupled by corresponding threads, set screws,retaining rings, interlocking splines, interlocking keys,interference/press fit, adhesives, and/or other means operable to lockthe drive shaft 252 and the rotor shaft 260 together and/or preventtheir relative rotation. However, in other implementations of the pumpassembly 200, the drive shaft 252 and the rotor shaft 260 may instead beintegrally formed as a single discrete member operable to move as asingle unit. For the electric motors 250 to be mounted about the mainjournals 264, each motor 250 may comprise a width (i.e., length alongthe central axis 268) that may permit mounting between adjacent crankpinjournals 266. However, one or more of the main journals 264 may comprisea width that may permit mounting of a wider electric motor 250 betweenthe adjacent crankpin journals 266.

In still other implementations of the pump assembly 200, the drive shaft252 may comprise a plurality of discrete and/or otherwise separableportions adapted to be interconnected. For example, the main journals264 and the crankpin journals 266 may comprise discrete and/or separablemembers, which may be coupled together to form the drive shaft 252.These separable main journals 264 and crankpin journals 266 may befixedly coupled by corresponding threads, bolts, set screws, retainingrings, interlocking splines, interlocking keys, interference/press fit,adhesives, and/or other means operable to couple the separable mainjournals 264 and crankpin journals 266 together and prevent theirrelative rotation. Furthermore, the rotor shafts 260 of the electricmotor 250 may be or comprise solid members (i.e., not comprising thecentral bore), which may also be or serve as the separable main journals264, such as may be operable to fixedly couple with the separablecrankpin journals 266 to form the drive shaft 252. Such configurationmay permit piece-by-piece or modular assembly and/or construction of thedrive shaft and/or the power section 202 of the pump assembly 200.

As depicted in FIG. 4, the main journals 264 may comprise an outerdiameter that is substantially the same or slightly smaller than thediameter of the axial bore 261 of the rotor shaft 260, such as mayfacilitate direct and/or otherwise fixed connection between the mainjournals 264 and the rotor shaft 260. However, the electric motor 250may be configured such that the axial bore 261 extending through therotor shaft 260 may comprise an inner diameter that is greater than themaximum outer diameter of the drive shaft 252, or be adapted tosimultaneously enclose the three crankpin journals 266, thus permittingthe drive shaft 252 to be translated axially therethrough, such asduring assembly and/or maintenance. In such implementations, the innerdiameter of the bore 261 may be substantially the same or similar tothat of a stator axial opening 316 shown in FIGS. 5 and 6, and theintermediate member (such as the ring, not shown), may be utilized toextend between and/or fixedly couple the rotor shaft 260 with the mainjournals 264.

The drive shaft 252 and the rotor 258 may be supported in positionwithin the stator 256 by the power section housing 254, wherein thesupport journals 262 may extend through opposing openings 272 in thepower section housing 254. To facilitate rotation of the drive shaft 252within the power section housing 254, one or more bearings 270 may bedisposed about the support journals 262 and against the side surfaces ofthe openings 272. A cover plate 274 and/or other means for protectionmay enclose the bearings 270.

Referring again to FIGS. 3 and 4, the power section housing 254 and thepump housing 216 may be coupled together via an intermediate housing280. For example, the pump housing 216 may be fastened with theintermediate housing 280 by a plurality of threaded fasteners 282, andthe intermediate housing 280 may be fastened with the power sectionhousing 254 by another plurality of threaded fasteners 284. Theintermediate housing 280 may further comprise an access door 298, whichmay facilitate access to portions of the pump assembly 200, such asduring assembly and/or maintenance of the pump assembly 200.

To transform and transmit the rotational motion of the drive shaft 252to a reciprocating linear motion of the plungers 222, a plurality ofcrosshead mechanisms 285, comprising a plurality of connecting members,may be utilized. For example, each crosshead mechanism 285 may comprisea connecting rod 286 pivotally coupled with a corresponding crankpinjournal 266 at one end and with a pin 288 of a crosshead 290 at anopposing end. During pumping operations, inner walls of the intermediatehousing 280 may guide each crosshead 290, such as may reduce oreliminate lateral motion of each crosshead 290. Each crosshead mechanism285 may further comprise a piston rod 292 coupling the crosshead 290with the reciprocating member 222. The piston rod 292 may be coupledwith the crosshead 290 via a threaded connection 294 and with thereciprocating member 222 via a flexible connection 296.

For the electric motors 250 to be mounted about the main journals 264,each motor 250 may comprise a width that may permit mounting betweenadjacent connecting rods 286 rotatably coupled with adjacent crankpinjournals 266. However, one or more of the main journals 264 may comprisea greater width that may permit mounting of a wider electric motor 250between adjacent connecting rods 286. Accordingly, when the electricmotors 250 are powered, the rotors 258 transfer torque to the driveshaft 252, which, in turn, actuate the reciprocating members 222 via thecrosshead mechanisms 285 to cause the fluid section 210 to pump fluidfrom the fluid inlet conduit 226 to the fluid outlet conduit 235.

FIG. 5 is a side sectional view of a portion of another exampleimplementation of the pump assembly 200 shown in FIG. 1, designatedherein by reference numeral 300, according to one or more aspects of thepresent disclosure. FIG. 6 is a top partial sectional view of a portionof the pump assembly 300 shown in FIG. 5 according to one or moreaspects of the present disclosure. For simplicity and clarity,components of the pump assembly 300 comprising the same or similarstructure and/or function as corresponding components of the pumpassembly 200 will be identified using the same numerals.

Referring to FIGS. 5 and 6, collectively, the pump assembly 300 maycomprise a fluid section 210, an intermediate housing 280, and aplurality of crosshead mechanisms 285, as described above. The pumpassembly 300 may further comprise a power section 302 having a powersection housing 304 enclosing an electric motor 306, which may bedisposed about a drive shaft 308. The electric motor 306 is operable todrive or otherwise rotate the drive shaft 308. The electric motor 306comprises a motor housing 310 enclosing a stator 312 and a rotorassembly. The rotor assembly comprises a plurality of rotor sections orrotors 314 surrounded by the stator 312.

The stator 312 may be a single-piece or otherwise continuous membercomprising one or more field coils or windings enclosed within the motorhousing 310, such as may generate a magnetic field when powered byelectric current from the source of electric power 148. The stator 312includes an axial opening 316 in which the plurality of rotors 314 andthe drive shaft 308 extend. The stator 314 and the motor housing 310 mayfurther comprise a plurality of lateral openings 318 extending from theaxial opening 316 to the exterior of the electric motor 306 toward thecrossheads 290. The connecting rods 286 extend through the lateralopenings 318 and pivotally couple the drive shaft 308 with thecrossheads 290.

The rotors 314 comprise a plurality of permanent magnets 320 fixedlydisposed about each rotor shaft 322 along the length of each rotor 314.The rotor shafts 322 may be hollow shafts or comprise a bore throughwhich the drive shaft 308 extends. The rotor shafts 322 or other portionof the rotors 314 are directly and/or otherwise fixedly coupled with thedrive shaft 308, such that the rotor shafts 322 transmit torque from therotors 314 directly to the drive shaft 308. To prevent relative rotationbetween the power section housing 304 and the motor 306, the powersection housing 304 and the motor housing 310 may be fixedly coupledtogether. Because the rotor shafts 322 and the drive shaft 308 aredirectly and/or otherwise fixedly coupled, the rotor shafts 322 and thedrive shaft 308 may rotate at the same speed or rate. However, the driveshaft 308 and the rotor shafts 322 may instead be integrally formed as asingle discrete member operable to move as a single unit.

FIGS. 5 and 6 show the drive shaft 308 implemented as a crankshaftcomprising a plurality of support journals 324, main journals 326, andcrankpin journals 328. The support and main journals 324, 326 may extendalong a central axis of rotation 330 of the drive shaft 308, while thecrankpin journals 328 may be offset from the central axis of rotation330 by a predetermined distance and spaced 120 degrees apart withrespect to the support journals 324 and the main journals 326.Accordingly, the axial opening 316 may comprise an inner diameter thatis greater than the maximum outer diameter of the drive shaft 308, or beotherwise adapted to simultaneously enclose the crankpin journals 328,such as to permit the crankpin journals 328 and/or the rotors 314 torotate without contacting the stator 312.

The main journals 326 and the rotor shafts 322 may be fixedly coupled,such as described above, while the crankpin journals 328 and theconnecting rods 286 may be rotatably coupled, such as described above.The drive shaft 308 and the rotors 314 may be supported in positionwithin the stator 312 by the power section housing 304 and the bearings270, such as described above. Accordingly, when the electric motor 306is powered, the rotors 314 transfer torque to the drive shaft 308,which, in turn, actuate the reciprocating members via the crossheadmechanisms 285 to cause the fluid section 210 to pump fluid.

FIG. 7 is a top partial sectional view of a portion of an exampleimplementation of the pump assembly 200 shown in FIG. 1, designatedherein by reference numeral 400, according to one or more aspects of thepresent disclosure. For simplicity and clarity, components of the pumpassembly 400 comprising the same or similar structure and/or function ascorresponding components of the pump assembly 200 will be identifiedusing the same numerals.

The pump assembly 400 may comprise a fluid section 210, an intermediatehousing 280, and a plurality of crosshead mechanisms 285, as describedabove. The pump assembly 400 may further comprise a power section 402having a power section housing 404 partially enclosing a drive shaft406. The pump assembly may further comprise two or more electric motors408 coupled with opposing support journals 410 of the drive shaft 406extending out of the power section housing 404, wherein the electricmotors 408 may be operable to drive or otherwise rotate the drive shaft406. The electric motors 408 may comprise the same or similar structureand/or function as the electric motors 250 described above, such ascomprising a motor housing 255 enclosing a stator 256 and a rotor 258.

Each rotor 258 may comprise a rotor shaft 260 having a bore extendingtherethrough, such as may contain therein the support journals 410 orend portions of the drive shaft 406. The rotor shafts 260 or otherportion of the rotors 258 are directly and/or otherwise fixedly coupledwith the drive shaft 406, such that the rotor shafts 260 may transmittorque from the rotors 258 directly to the drive shaft 406. Thus,because the rotor shafts 260 and the drive shaft 406 are directly and/orfixedly coupled, the rotor shafts 260 and the drive shaft 406 may rotateat the same speed or rate. However, the drive shaft 406 and the rotorshafts 260 may instead be integrally formed as a single discrete memberoperable to move as a single unit. To prevent relative rotation betweenthe power section housing 404 and the motors 408, the power sectionhousing 404 and motor housing 255 may be fixedly coupled together or toa fixed base (not shown).

FIG. 7 shows the drive shaft 406 being implemented as a crankshaftcomprising a plurality of main journals 412 and crankpin journals 414.The support and main journals 410, 412 may extend along the central axisof rotation 416 of the drive shaft 406, while the crankpin journals 414may be offset from the central axis of rotation 416 by a predetermineddistance and spaced 120 degrees apart with respect to the supportjournals 410 and the main journals 412.

The support journals 410 and the rotor shafts 260 may be fixedlycoupled, such as described above, while the crankpin journals 414 andconnecting rods 286 may be rotatably coupled, such as described above.The drive shaft 406 may be supported in position within the powersection 402 by the power section housing 404 and the bearings 270, suchas described above. Accordingly, when the electric motors 408 arepowered, the rotors 258 transfer torque to the drive shaft 406, which,in turn, actuate the reciprocating members via the crosshead mechanisms285 to cause the fluid section 210 to pump fluid.

The pump assembly 200 shown in FIG. 1 may be further implemented withmultiple fluid sections 210, such that each pump assembly 200 maycomprise a fluid section 210 on opposing sides of a centrally locatedpower section 202, 302, 402. For example, FIG. 8 is a top partialsectional view of a portion of such an implementation of the pumpassembly 200 shown in FIG. 1, designated herein by reference numeral500, according to one or more aspects of the present disclosure. Forsimplicity and clarity, components of the pump assembly 500 comprisingthe same or similar structure and/or function as correspondingcomponents of the pump assembly 200 will be identified using the samenumerals.

The pump assembly 500 may comprise opposing fluid sections 210,intermediate housings 280, and crosshead mechanisms 285, as describedabove. The pump assembly 500 may further comprise a power section 502having a power section housing 504 enclosing an electric motor 506,which may be disposed about a drive shaft 508. The electric motor 506 isoperable to drive or otherwise rotate the drive shaft 508. The electricmotor 506 may comprise a motor housing 510 enclosing a stator 512 and arotor assembly. The rotor assembly comprises a plurality of rotorsections or rotors 514 surrounded by the stator 512.

The stator 512 may be a single-piece or continuous member comprising oneor more field coils or windings enclosed within the motor housing 510,such as may generate a magnetic field when powered by electric currentfrom the source of electric power 148 or another source of electricpower. The stator 512 may include an axial opening 516 through which theplurality of rotors 514 and the drive shaft 508 extend. The stator 514and the motor housing 510 may further comprise a plurality of opposinglateral openings 518 extending from the axial opening 516 to theexterior of the electric motor 506 toward the crossheads 290. Thelateral openings 518 may permit the opposing connecting rods 286 toextend therethrough and pivotally couple the drive shaft 508 with thecrossheads 290.

The rotors 514 comprise a plurality of permanent magnets 520 fixedlydisposed about the rotor shafts 522. Each rotor shaft 522 may be ahollow shaft or comprise a bore through which the drive shaft 508extends. The rotor shafts 522 or other portion of the rotors 514 may bedirectly and/or otherwise fixedly coupled with the drive shaft 508, suchthat the rotor shafts 522 transmit torque from the rotors 514 directlyto the drive shaft 508. To prevent relative rotation between the powersection housing 504 and the motor 506, the power section housing 504 andmotor housing 510 may be fixedly coupled together. Because the rotorshafts 522 and the drive shaft 508 are directly and/or otherwise fixedlycoupled, the rotor shafts 522 and the drive shaft 508 rotate at the samespeed or rate. However, the drive shaft 508 and the rotor shafts 522 mayinstead be integrally formed as a single discrete member operable tomove as a single unit.

FIG. 8 shows the drive shaft 508 implemented as a crankshaft comprisinga plurality of support journals 524, main journals 526, and crankpinjournals 528. The support and main journals 524, 526 may extend alongthe central axis of rotation 530 of the drive shaft 508, while thecrankpin journals 528 may be offset from the central axis of rotation530 by a predetermined distance and spaced 120 degrees apart withrespect to the support journals 524 and the main journals 526.Accordingly, the axial opening 516 may comprise an inner diameter thatis greater than the maximum outer diameter of the drive shaft 508, or beadapted to simultaneously enclose the crankpin journals 528, such as topermit the crankpin journals 528 and/or the rotors 514 to rotate withoutcontacting the stator 512.

The main journals 526 and the rotor shafts 522 may be fixedly coupled,such as described above, while the crankpin journals 528 and theconnecting rods 286 may be rotatably coupled, such as may permit eachconnecting rod 286 to pivot independently of the opposing connecting rod286. The drive shaft 508 and the rotors 514 may be supported in positionwithin the stator 512 by the power section housing 504 and bearings 270,such as described above. Accordingly, when the electric motor 506 ispowered, the rotors 514 may transfer torque directly to the drive shaft508, which, in turn, may actuate the reciprocating members via thecrosshead mechanisms 285 to cause the opposing fluid sections 210 topump fluid.

FIG. 8 shows the pump assembly 500 comprising two fluid sections 210connected with a single power section 502. The power section 502 maycomprise a similar structure and/or function as the power section 302described above. However, it should be understood that otherimplementations of the pump assemblies 200, 300, 400, 500 comprisingmultiple fluid sections 210 connected with a single power section(comprising the same or similar structure and/or function as the powersections 202, 402 described above) are also within the scope of thepresent disclosure.

Although FIG. 8 shows two fluid sections 210 connected to a single powersection 502 and spaced 180 degrees apart with respect to the centralaxis of rotation 530, in other implementations, the pump assembly 500may comprise additional fluid sections 210 connected to a singlecentrally-located power section 502. For example, the pump assembly 500may comprise three fluid sections 210, each connected to thecentrally-located power section 502 in the same or similar manner asshowed in FIG. 8 and spaced 120 degrees apart with respect to thecentral axis of rotation 530. In another implementation, the pumpassembly 500 may comprise four fluid sections 210, each connected to thecentrally-located power section 502 in the same or similar manner asshown in FIG. 8 and spaced ninety degrees apart with respect to thecentral axis of rotation 530. Other implementations of the pump assembly500 comprising additional quantities of fluid sections 210 coupled withthe centrally-located power section 502 are also within the scope of thepresent disclosure.

Although FIGS. 2-8 show the pump assembly 200 as a triplex reciprocatingpump assembly comprising three fluid chambers 218 and threereciprocating members 222, other implementations within the scope of thepresent disclosure may include the pump assembly 200 as or comprising aquintuplex reciprocating pump assembly comprising five fluid chambers218 and five reciprocating members 222, or other numbers of fluidchambers 218 and reciprocating members 222. It is also noted that theelectric motors 250, 306, 408, 506 described above may be or compriseliquid cooled motors, such as in implementations in which one or morewater jacket configurations (not shown) may be utilized to remove heatfrom the electric motors during operations.

In still other implementations of the pumping system 100, two or moreadjacent pump assemblies 200 within a pump fleet may be operativelycoupled together, such as to help synchronize the pumps and/orfacilitate torque sharing between the pump assemblies 200. For example,two or more adjacent pump assemblies 200 may comprise drive shafts 252extending past the housing 254 or the cover plate 274. The two or moreadjacent pump assemblies 200 may be positioned such that the driveshafts 252 are aligned substantially along their central axes ofrotation 268 to permit the drive shafts 252 to be coupled together. Thedrive shafts 252 may be coupled by means known in the art, includingchain couplings, jaw couplings, rigid couplings, flexible couplings,spline shafts, and universal joints, among other examples.

FIG. 9 is a schematic view of a portion of another exampleimplementation of the pump assembly 200 shown in FIG. 1, designatedherein by reference numeral 600, according to one or more aspects of thepresent disclosure. For simplicity and clarity, components of the pumpassembly 600 comprising the same or similar structure and/or function asthe corresponding components of the pump assembly 200 will be identifiedusing the same numerals.

The pump assembly 600 may comprise a power section 602 coupled with afluid section 604. The power section 602 may comprise a motor 250 havinga motor housing 255 enclosing a stator 256 and a rotor 258. The fluidsection 604 may comprise a drive shaft 606 coupled with a rotary swashplate 608, which may be coupled with a swing swash plate 610. The fluidsection 604 may further comprise a plurality of cylinders 612, eachdefining a fluid chamber 614 therein, and a plurality of reciprocatingmembers 616 slidably movable within the fluid chambers 614. The swingswash plate 610 may be coupled with the plurality of reciprocatingmembers 616 by a plurality of connecting rods 618. The drive shaft 606,the rotary and swing swash plates 608, 610, the connecting rods 618, thereciprocating members 616, and the cylinders 612 may be enclosed withina fluid section housing 620. The motor housing 255 and the fluid sectionhousing 620 may be fixedly coupled, such as may prevent relative motiontherebetween during operations. The pump assembly 600 may furthercomprise one or more bearings 622 disposed about the drive shaft 606 andagainst the fluid section housing 620, such as may facilitate lowfriction rotation of the drive shaft 606 about a central axis ofrotation 623 with respect to the fluid section housing 620. The one ormore bearings 622 may further support the drive shaft 606 in positionwithin the fluid section housing 620.

The electric motor 250 may be coupled with a portion of the drive shaft606 extending out of the fluid section housing 620, and the electricmotor 250 may be operable to drive or otherwise rotate the drive shaft606. For example, the rotor 258 may comprise a rotor shaft 260 having anaxial bore 261 through which the portion of the drive shaft 606extending out of the fluid section housing 620 may extend. The rotorshaft 260 or other portion of the rotor 258 is directly and/or otherwisefixedly coupled with the drive shaft 606, such that the rotor shaft 260transmits torque from the rotor 258 directly to the drive shaft 606.Because the rotor shaft 260 and the drive shaft 606 are directly and/orotherwise fixedly coupled, the rotor shaft 260 and the drive shaft 606rotate at the same speed or rate. However, the drive shaft 606 and therotor shaft 260 may instead be integrally formed as a single discretemember operable to move as a single unit.

During pumping operations, the rotating drive shaft 606 rotates therotary swash plate 608, which, in turn, swings the swing swash plate610, causing the connecting rods 618 and the reciprocating members 616to oscillate back and forth, as indicated by arrows 624, 626. Theoscillating movement of the reciprocating members 616 sequentially drawsand discharges fluid into and out of the fluid chambers 614 throughinlet and outlet ports 628, 630. The pressurized fluid may becommunicated from the pump assembly 600 to the high-pressure inlet (notshown) of the manifold 136 or to another destination.

FIG. 10 is a flow-chart diagram of at least a portion of a method 700according to one or more aspects of the present disclosure. The method700 may be performed utilizing at least a portion of one or moreimplementations of the apparatus shown in one or more of FIGS. 1-9and/or otherwise within the scope of the present disclosure.

The method 700 comprises connecting (710) a fluid source to a pumpassembly. For example, the fluid source may be the manifold 136 shown inFIG. 1, and the pump assembly may be substantially similar to one ormore of the pump assemblies 200, 300, 400, 500, 600 shown in FIGS. 1-9.Thus, the pump assembly may comprise a drive shaft, a plurality of rodsoperatively coupled with the drive shaft, a plurality of reciprocatingmembers operatively coupled with a plurality of rods, and an electricmotor comprising a stator and a rotor that is directly and/or otherwisefixedly coupled with the drive shaft, wherein these components are asdescribed above. The electric motor is then operated (720) to rotate therotor and the drive shaft at the same speed, such that the rotatingdrive shaft moves the plurality of rods and reciprocating members topump the fluid from the fluid source through the pump assembly.

As described above, the electric motor may comprise an axial boreextending through the rotor, and the drive shaft may extend through theaxial bore. Thus, the rotating drive shaft rotates within the axialbore. Similarly, the drive shaft may comprise a crankshaft having aplurality of crankpin journals, operatively coupled with the pluralityof rods, and a plurality of main journals, connected with the rotor. Theelectric motor may comprise a plurality of openings extending laterallyfrom the axial bore, and operating (720) the electric motor to rotatethe rotor and the crankshaft may move the plurality of rods through theplurality of openings.

As also described above, the drive shaft may be a crankshaft, theelectric motor may be a first electric motor, the stator may be a firststator, the rotor may be a first rotor, and the pump assembly mayfurther comprise a second electric motor comprising a second stator anda second rotor, wherein the first and second electric motors may beseparated by a space, and the second rotor is directly connected withthe crankshaft. In such implementations, operating (720) the electricmotor may comprise operating the first and second electric motors torotate the first and second rotors and the crankshaft at the same speed,wherein the rotating crankshaft moves the plurality of rods through thespace between the first and second electric motors. The method (700) mayfurther comprise electrically connecting (730) the first and secondelectric motors to an electric power source, such as the electric powersource 148 shown in FIG. 1. The method (700) may further comprisesynchronizing (750) the speed of the first and second electric motorsand monitoring (740) speed of the first and second electric motors.

In view of the entirety of the present disclosure, including the figuresand the claims, a person having ordinary skill in the art should readilyrecognize that the present disclosure introduces an apparatuscomprising: a pump assembly, comprising: a drive shaft; a plurality ofrods operatively coupled with the drive shaft; a plurality ofreciprocating members each operatively coupled with a corresponding oneof the plurality of rods; and an electric motor operable to rotate thedrive shaft, wherein the electric motor comprises a rotor having a rotorshaft, wherein the rotor shaft is connected with the drive shaft,wherein the rotor shaft is operable to rotate the drive shaft and thusmove the plurality of rods and reciprocating members, wherein the rotorshaft and the drive shaft rotate at the same speed, and wherein theplurality of reciprocating members are operable to move a fluid.

The plurality of reciprocating members may comprise a plurality ofpistons, plungers, or diaphragms.

The rotor may further comprise a plurality of permanent magnets.

The electric motor may rotate at speeds between about zero RPM and 500RPM. For example, the electric motor may rotate at speeds between about300 and 400 RPM.

The pump assembly may not comprise a transmission operatively connectingthe rotor shaft and the drive shaft.

The rotor shaft and the drive shaft may be integral portions of a singlediscrete member.

The pump assembly may further comprise: a housing disposed about theelectric motor; and a bearing disposed intermediate the drive shaft andthe housing.

The pump assembly may further comprise a housing disposed about theplurality of rods and/or reciprocating members, and the electric motormay be connected with the housing.

The pump assembly may further comprise a swashplate connected with thedrive shaft, and the plurality of rods may be operatively coupled withthe swash plate.

The drive shaft may comprise a crankshaft, such as may comprise aplurality of main journals connected with the rotor shaft. In suchimplementations, the electric motor may be one of a plurality ofelectric motors collectively operable to rotate the crankshaft, each ofthe plurality of electric motors may comprise a rotor having a rotorshaft and a plurality of magnets, the rotor shaft of each of theplurality of electric motors may be connected with the crankshaft, therotor shaft of each of the plurality of electric motors may be operableto rotate the crankshaft and thus move corresponding ones of theplurality of rods, the rotor shaft of each of the plurality of electricmotors and the crankshaft may rotate at the same speed, the rotor shaftof at least one of the plurality of electric motors may comprise anaxial bore extending therethrough, the crankshaft may extend though theaxial bore, and at least one of the plurality of electric motors may bedisposed between two or more of the plurality of rods. Inimplementations in which the drive shaft comprises a crankshaft, thecrankshaft may comprise a plurality of crankpin journals operativelycoupled with a corresponding one of the plurality of rods, thecrankshaft may comprise a plurality main journals each connected with arotor shaft of a corresponding one of the plurality of electric motors,and at least one of the plurality of electric motors may be disposedbetween two or more of the plurality of crankpin journals.

The rotor shaft may comprise an axial bore extending longitudinallytherethrough, and the drive shaft may extend through the axial bore. Insuch implementations, the drive shaft may comprise a crankshaft, thecrankshaft may comprise a plurality of crankpin journals operativelycoupled with a corresponding one of the plurality of rods, thecrankshaft may comprise a plurality of main journals connected with therotor shaft, the electric motor may further comprise a plurality ofopenings extending laterally from the axial bore, and the plurality ofrods and/or crankpin journals may extend into the plurality of openings.

In at least one implementation, the electric motor may be a firstelectric motor, the rotor may be a first rotor, the rotor shaft may be afirst rotor shaft, the plurality of magnets may comprise a plurality offirst magnets, the pump assembly may further comprise a second electricmotor operable to rotate the drive shaft, the second electric motor maycomprise a second rotor having a second rotor shaft and a plurality ofsecond magnets, the second rotor shaft may be connected with the driveshaft, the second rotor shaft may be operable to rotate the drive shaftand thus move the plurality of rods, and the second rotor shaft and thedrive shaft may rotate at the same speed. In such implementation, thefirst rotor shaft may comprise a first axial bore extendinglongitudinally therethrough, the second rotor shaft may comprise asecond axial bore extending therethrough, the drive shaft may bedisposed within the first and second axial bores, and at least one ofthe first and second electric motors may be disposed between two or moreof the plurality of rods.

The present disclosure also introduces an apparatus comprising: a pumpassembly, comprising: a crankshaft comprising a plurality of mainjournals and a plurality of crankpin journals; a plurality of rods eachoperatively coupled with a corresponding one of the plurality ofcrankpin journals; a plurality of reciprocating members each operativelycoupled with a corresponding one of the plurality of rods; and anelectric motor operable to rotate the crankshaft, wherein the electricmotor comprises a stator and a rotor, wherein the rotor is directlyconnected with the crankshaft, and wherein the rotor is operable torotate the crankshaft and thus move the plurality of rods, therebycausing the plurality of reciprocating members to move a fluid.

The plurality of reciprocating members may comprise a plurality ofpistons, plungers, or diaphragms.

The rotor may further comprise a plurality of permanent magnets.

The electric motor may rotate at speeds between about zero RPM and 500RPM. For example, the electric motor may rotate at speeds between about300 RPM and 400 RPM.

The pump assembly may further comprise: a housing disposed about theelectric motor; and a bearing disposed intermediate the crankshaft andthe housing.

The pump assembly may further comprise a housing disposed about theplurality of rods and/or reciprocating members, and the electric motormay be connected with the housing.

The rotor may further comprise a rotor shaft, and the rotor shaft may beconnected with the crankshaft. The rotor shaft may be connected with atleast one of the plurality of main journals. The rotor shaft maycomprise an axial bore extending longitudinally therethrough, and thecrankshaft may extend through the axial bore. The plurality of crankpinjournals may be operatively coupled with a corresponding one of theplurality of rods, the plurality of main journals may be connected withthe rotor shaft, the electric motor may further comprise a plurality ofopenings extending laterally from the axial bore, and the plurality ofrods and/or crankpin journals may extend into the plurality of openings.The pump assembly may not comprise a transmission operatively connectingthe rotor shaft and the crankshaft. The rotor shaft and the crankshaftmay be integral portions of a single discrete member. The crankshaft maycomprise a plurality of main journals connected with the rotor shaft.The electric motor may be one of a plurality of electric motors operableto rotate the crankshaft, the rotor shaft may be operable to rotate thecrankshaft and thus move the plurality of rods and reciprocatingmembers, the rotor shaft and the crankshaft may rotate at the samespeed, at least one rotor shaft may comprise an axial bore extendingtherethrough, the crankshaft may extend though the axial bore, and atleast one of the plurality of electric motors may be disposed betweentwo or more of the plurality of rods. The crankshaft may comprise aplurality of crankpin journals operatively coupled with a correspondingone of the plurality of rods, the crankshaft may comprise a pluralitymain journals connected with a corresponding rotor shaft, and at leastone of the plurality of electric motors may disposed between two or moreof the plurality of crankpin journals. The electric motor may be a firstelectric motor, the rotor may be a first rotor, the rotor shaft may be afirst rotor shaft, the pump assembly may further comprise a secondelectric motor operable to rotate the crankshaft, the second electricmotor may comprise a second rotor having a second rotor shaft, thesecond rotor shaft may be connected with the crankshaft, the secondrotor shaft may be operable to rotate the crankshaft and thus move theplurality of rods and reciprocating members, and the second rotor shaftand the crankshaft may rotate at the same speed. The first rotor shaftmay comprise a first axial bore extending longitudinally therethrough,the second rotor shaft may comprise a second axial bore extendingtherethrough, the crankshaft may be disposed within the first and secondaxial bores, and at least one of the first and second electric motorsmay be disposed between two or more of the plurality of rods.

The present disclosure also introduces a method comprising: connecting afluid source to a pump assembly comprising: a drive shaft; a pluralityof rods operatively coupled with the drive shaft; a plurality ofreciprocating members operatively coupled with a plurality of rods; andan electric motor comprising a stator and a rotor that is directlyconnected with the drive shaft; and operating the electric motor torotate the rotor and the drive shaft at the same speed such that therotating drive shaft moves the plurality of rods and reciprocatingmembers to pump the fluid from the fluid source through the pumpassembly.

The electric motor may comprise an axial bore extending through therotor, the drive shaft may extend through the axial bore, and therotating drive shaft may rotate within the axial bore. The drive shaftmay comprise a crankshaft, the crankshaft may comprise a plurality ofcrankpin journals operatively coupled with the plurality of rods, thecrankshaft may comprise a plurality of main journals connected with therotor, the electric motor may comprise a plurality of openings extendinglaterally from the axial bore, and operating the electric motor torotate the rotor and the crankshaft may move the plurality of rodsthrough the plurality of openings.

The drive shaft may be a crankshaft, the electric motor may be a firstelectric motor, the stator may be a first stator, the rotor may be afirst rotor, the pump assembly may further comprise a second electricmotor comprising a second stator and a second rotor, the first andsecond electric motors may be separated by a space, the second rotor maybe directly connected with the crankshaft, and the method may furthercomprise operating the second electric motor to rotate the second rotorand the crankshaft at the same speed, wherein the rotating crankshaftmay move the plurality of rods through the space between the first andsecond electric motors. The method may further comprise electricallyconnecting the first and second electric motors to an electric powersource. The method may further comprise: synchronizing the speed of thefirst and second electric motors; and monitoring speed of the first andsecond electric motors. The first electric motor may comprise a firstaxial bore extending through the first rotor, the second electric motormay comprise a second axial bore extending through the second rotor, thecrankshaft may extend through the first and second axial bores, and therotating crankshaft may rotate within the first and second axial bores.The crankshaft may comprise a plurality of crankpin journals operativelycoupled with the plurality of rods, the crankshaft may comprise a firstmain journal coupled with the first rotor, the crankshaft may comprise asecond main journal coupled with the second rotor, and the rotatingcrankshaft may move at least one of the plurality of crankpin journalsthrough the space between the first and second electric motors.

The foregoing outlines features of several embodiments so that a personhaving ordinary skill in the art may better understand the aspects ofthe present disclosure. A person having ordinary skill in the art shouldappreciate that they may readily use the present disclosure as a basisfor designing or modifying other processes and structures for carryingout the same functions and/or achieving the same benefits of theembodiments introduced herein. A person having ordinary skill in the artshould also realize that such equivalent constructions do not departfrom the spirit and scope of the present disclosure, and that they maymake various changes, substitutions and alterations herein withoutdeparting from the spirit and scope of the present disclosure.

The Abstract at the end of this disclosure is provided to comply with 37C.F.R. §1.72(b) to permit the reader to quickly ascertain the nature ofthe technical disclosure. It is submitted with the understanding that itwill not be used to interpret or limit the scope or meaning of theclaims.

What is claimed is:
 1. An apparatus, comprising: a pump assembly,comprising: a drive shaft; a plurality of rods operatively coupled withthe drive shaft; a plurality of reciprocating members each operativelycoupled with a corresponding one of the plurality of rods; and anelectric motor operable to rotate the drive shaft, wherein the electricmotor comprises a rotor having a rotor shaft, wherein the rotor shaft isconnected with the drive shaft, wherein the rotor shaft is operable torotate the drive shaft and thus move the plurality of rods andreciprocating members, wherein the rotor shaft and the drive shaftrotate at the same speed, and wherein the plurality of reciprocatingmembers are operable to move a fluid.
 2. The apparatus of claim 1wherein the rotor further comprises a plurality of permanent magnets. 3.The apparatus of claim 1 wherein the pump assembly does not comprise atransmission operatively connecting the rotor shaft and the drive shaft.4. The apparatus of claim 1 wherein the rotor shaft and the drive shaftare integral portions of a single discrete member.
 5. The apparatus ofclaim 1 wherein the pump assembly further comprises a swashplateconnected with the drive shaft, and wherein each of the plurality ofrods is operatively coupled with the swash plate.
 6. The apparatus ofclaim 1 wherein the drive shaft comprises a crankshaft that includes aplurality of main journals connected with the rotor shaft.
 7. Theapparatus of claim 1 wherein: the drive shaft comprises a crankshaft;the electric motor is one of a plurality of electric motors collectivelyoperable to rotate the crankshaft; each of the plurality of electricmotors comprises a rotor having a rotor shaft and a plurality ofmagnets; the rotor shaft of each of the plurality of electric motors isconnected with the crankshaft; the rotor shaft of each of the pluralityof electric motors is operable to rotate the crankshaft and thus move acorresponding one of the plurality of rods; the rotor shaft of each ofthe plurality of electric motors and the crankshaft rotate at the samespeed; the rotor shaft of at least one of the plurality of electricmotors comprises an axial bore extending therethrough; the crankshaftextends though the axial bore; and at least one of the plurality ofelectric motors is disposed between two or more of the plurality ofrods.
 8. The apparatus of claim 1 wherein: the drive shaft comprises acrankshaft; the electric motor is one of a plurality of electric motorscollectively operable to rotate the crankshaft; the crankshaft comprisesa plurality of crankpin journals each operatively coupled with acorresponding one of the plurality of rods; the crankshaft comprises aplurality main journals each connected with a rotor shaft of acorresponding one of the plurality of electric motors; and at least oneof the plurality of electric motors is disposed between two or more ofthe plurality of crankpin journals.
 9. The apparatus of claim 1 whereinthe rotor shaft comprises an axial bore extending longitudinallytherethrough, and wherein the drive shaft extends through the axialbore.
 10. The apparatus of claim 1 wherein: the electric motor is afirst electric motor; the rotor is a first rotor; the rotor shaft is afirst rotor shaft; the plurality of magnets comprises a plurality offirst magnets; the pump assembly further comprises a second electricmotor operable to rotate the drive shaft; the second electric motorcomprises a second rotor having a second rotor shaft and a plurality ofsecond magnets; the second rotor shaft is connected with the driveshaft; the second rotor shaft is operable to rotate the drive shaft andthus move the plurality of rods; and the second rotor shaft and thedrive shaft rotate at the same speed.
 11. The apparatus of claim 10wherein: the first rotor shaft comprises a first axial bore extendinglongitudinally therethrough; the second rotor shaft comprises a secondaxial bore extending therethrough; the drive shaft is disposed withinthe first and second axial bores; and at least one of the first andsecond electric motors is disposed between two or more of the pluralityof rods.
 12. An apparatus, comprising: a pump assembly, comprising: acrankshaft comprising a plurality of main journals and a plurality ofcrankpin journals; a plurality of rods each operatively coupled with acorresponding one of the plurality of crankpin journals; a plurality ofreciprocating members each operatively coupled with a corresponding oneof the plurality of rods; and an electric motor operable to rotate thecrankshaft, wherein the electric motor comprises a stator and a rotor,wherein the rotor is directly connected with the crankshaft, and whereinthe rotor is operable to rotate the crankshaft and thus move theplurality of rods, thereby causing the plurality of reciprocatingmembers to move a fluid.
 13. The apparatus of claim 12 wherein the rotorfurther comprises a plurality of permanent magnets.
 14. The apparatus ofclaim 12 wherein the rotor further comprises a rotor shaft, and whereinthe rotor shaft is connected with the crankshaft and at least one of theplurality of main journals.
 15. The apparatus of claim 14 wherein therotor shaft comprises an axial bore extending longitudinallytherethrough, and wherein the crankshaft extends through the axial bore.16. A method, comprising: connecting a fluid source to a pump assemblycomprising: a drive shaft; a plurality of rods operatively coupled withthe drive shaft; a plurality of reciprocating members operativelycoupled with the plurality of rods; and an electric motor comprising astator and a rotor that is directly connected with the drive shaft; andoperating the electric motor to rotate the rotor and the drive shaft atthe same speed such that the rotating drive shaft moves the plurality ofrods and reciprocating members to pump the fluid from the fluid sourcethrough the pump assembly.
 17. The method of claim 16 wherein: theelectric motor comprises an axial bore extending through the rotor; thedrive shaft extends through the axial bore; the rotating drive shaftrotates within the axial bore; the drive shaft comprises a crankshaft;the crankshaft comprises a plurality of crankpin journals operativelycoupled with the plurality of rods; the crankshaft comprises a pluralityof main journals connected with the rotor; the electric motor comprisesa plurality of openings extending laterally from the axial bore; andoperating the electric motor to rotate the rotor and the crankshaftmoves the plurality of rods through the plurality of openings.
 18. Themethod of claim 16 wherein: the drive shaft is a crankshaft; theelectric motor is a first electric motor; the stator is a first stator;the rotor is a first rotor; the pump assembly further comprises a secondelectric motor comprising a second stator and a second rotor; the firstand second electric motors are separated by a space; the second rotor isdirectly connected with the crankshaft; and the method further comprisesoperating the second electric motor to rotate the second rotor and thecrankshaft at the same speed, wherein the rotating crankshaft moves theplurality of rods through the space between the first and secondelectric motors.
 19. The method of claim 18 further comprisingelectrically connecting the first and second electric motors to anelectric power source.
 20. The method of claim 18 further comprising:synchronizing the speed of the first and second electric motors; andmonitoring speed of the first and second electric motors.